Leo Kulaš, a native of the Croatian town of Metković, studied costume and fashion design at the Academy of Fine Arts in Belgrade. Since 1983, when he created his first costume designs, he has designed costumes for over 200 drama productions, ballets, operas, films and television programmes. He has worked with renowned directors such as Eduard Miler, Diego de Brea, Matthias Davids, Plamen Kartaloff, and Janusz Kica and famous theatres such as the Hannover State Opera, the Thalia Theater in Hamburg, the Landestheater in Linz, the State Opera in Vienna, the Latvian National Opera and the Bolshoi Theatre in Moscow.

Recent works include the costume designs for the musical Les Misérables and the opera Electra (Sofia Opera, 2020).

He has been working with the choreographer Edward Clug for over twenty years. He designed the costumes for his early works Tango (1998) and Radio & Juliet (2005), as well as later ballets such as Patterns in ¾ (2019, Stuttgart Ballet), Carmina Burana (2019, Les Grands Ballets Canadiens de Montréal) and Aperture (2019, Nederlands Dans Theater), to name a few. In the 2022/23 season, he designed the costumes for Clug's full-length ballet Coppélia for Theater Basel.

He received the Maribor Theatre Festival Award and the Prešeren Fund Award for his costumes for the Divine Comedy production (Slovenian National Theatre in Maribor) and the Maribor Theatre Festival Award for his costumes for Das Käthchen von Heilbronn.